A thermoresponsive system of a nanoemulsion-based gel with favorable characteristics to enhanced oil recovery (EOR) application is presented. A full factorial design study with different formulations of thermosensitive nanoemulsion-based gels was performed to assess the influence of the oil chain length, concentration of polyethylene glycol (PEG 400) and concentration of oil on the rheological behavior of the system. A formulation with low viscosity at room temperature and high viscosity at the temperature of the oil extraction well was presented. Hexane (6-carbon chain), capric acid (10-carbon chain) and isopropyl myristate (17-carbon chain) were used in concentrations of 5%, 10%, 15% and 20% wt%, also varying the concentration of PEG 400 in 0%, 3%, 6% and 9% wt%. The thermosensitive polymer used was a mixture of Pluronic® F-127 and Pluronic® F-68 6:1 wt% at 4.7% concentration. The surfactants used were Tween 80 and Span 80 (HLB = 13) at 20%. The formulation containing 20% isopropyl myristate (IPM) without the addition of PEG 400 showed a better response, with an increase in viscosity of more than 38 times in relation to its viscosity at 25 °C, and the maximum viscosity was reached at 53 °C. This is a promising formulation for EOR technology.

In the present study, high surface area boehmite nanopowder was recovered from aluminum cans waste. The sodium aluminate solution was first prepared by dissolving aluminum cans in NaOH solution and then, H2O2 solution was added to precipitate boehmite. The prepared boehmite was characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) and N2 adsorption–desorption techniques. The thermal stability of the boehmite sample was investigated using thermogravimetry (TG) and differential scanning calorimetry (DSC) techniques. The feasibility of using the prepared boehmite powder as a new low-cost adsorbent for the treatment of oilfield produced water was investigated. For comparison, commercial activated carbon was used for the treatment of the produced water under the same conditions. The efficiency of both of boehmite and activated carbon in the treatment of produced water was determined by monitoring the values of a number of pollution indicators [i.e. turbidity, sulfides, sulfates, total organic carbon (TOC), total petroleum hydrocarbon (TPH), and chemical oxygen demand (COD)] before and after the treatment. The boehmite powder showed very good efficiency in the treatment of the produced water, which is very close to that of commercial activated carbon under the same conditions. The effect of adsorbent dose, treatment time, and pH of the media on the adsorption efficiency of both of boehmite and activated carbon was examined at room temperature using chemical oxygen demand as a pollution indicator. The maximum capacity for COD reduction was 69.6% for boehmite and 83.5% for activated carbon at 40 g/l adsorbent dosage, pH7, and 24-h contact time.Graphic abstract

Catalysts to produce the important petrochemicals like benzene, toluene, and xylene (BTX) from refinery feedstocks, like light cycle oil (LCO) are reviewed here by covering published papers using model mixtures and real feeds. Model compounds experiments like tetralin and naphthalene derivatives provided a 53–55% total BTX yield. Higher yields were never attained due to the inevitable gas formation and other C9+-alkylbenzenes formed. For tetralin, the best catalysts are those conformed by Ni, CoMo, NiMo, or NiSn over zeolite H-Beta. For naphthalene derivatives, the best catalysts were those conformed by W and NiW over zeolite H-Beta silylated. Real feeds produced a total BTX yield of up to 35% at the best experimental conditions. Higher yields were never reached due to the presence of other types of hydrocarbons in the feed which can compete for the catalytic sites. The best catalysts were those conformed by Mo, CoMo, or NiMo over zeolite H-Beta. Some improvements were obtained by adding ZSM-5 to the support or in mixtures with other catalysts.

Metallic composites represent a vital class of materials that has gained increased attention in crude oil processing as well as the production of biofuel from other sources in recent times. Several catalytic materials have been reported in the literature for catalytic cracking, particularly, of crude oil. This review seeks to provide a comprehensive overview of existing and emerging methods/technologies such as metal–organic frameworks (MOFs), metal–matrix composites (MMCs), and catalytic support materials, to bridge information gaps toward sustainable advancement in catalysis for petrochemical processes. There is an increase in industrial and environmental concern emanating from the sulphur levels of oils, hence the need to develop more efficient catalysts in the hydrotreatment (HDS and HDN) processes, and combating the challenge of catalyst poisoning and deactivation; in a bid to improving the overall quality of oils and sustainable use of catalyst. Structural improvement, high thermal stability, enhanced cracking potential, and environmental sustainability represent the various benefits accrued to the use of metallic composites as opposed to conventional catalysts employed in catalytic cracking processes.

Herein an efficient approach to produce functional polypropylene via solvent assisted solid-phase grafting process is reported, in which acrylic acid, methyl methacrylate and maleic anhydride are used as multi-monomers, 2,2′-azobis(2-methylpropionitrile) as initiator and ether as swelling solvent and carrier. The effects of various factors such as the swelling solvent species and dosage, swelling time and temperature, monomer and initiator concentrations, reaction time and temperature, nitrogen flow rate and the stirring speed on the grafting percentage and grafting efficiency were investigated. To verify the polar species was grafted onto polypropylene, the resulted polymers were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction analysis, water contact angle measurement, tensile strength and melt flow rate measurement. All the results showed that using the ether assisted solid-phase free radical grafting process is an efficient and versatile approach to produce functional polypropylene.

About half of the product from iron-based high-temperature Fischer–Tropsch synthesis is an aqueous product containing dissolved oxygenates. Volatile oxygenates can be recovered by distillation, but the bulk of the carboxylic acids remain in the water, which is called acid water. Fractional freezing was explored as a process for producing a more concentrated carboxylic acid solution from which the carboxylic acids could be recovered as petrochemical products, while concomitantly producing a cleaner wastewater. Solid–liquid equilibrium data were collected for aqueous solutions of acetic acid, propionic acid, and butyric acid. A synthetic Fischer–Tropsch acid water mixture (0.70 wt% acetic acid, 0.15 wt% propionic acid, and 0.15 wt% butyric acid) was prepared and the liquid phase concentrations of the acid species at solid–liquid equilibrium were determined. Control experiments with material balance closure on each of the carboxylic acid species were performed at selected conditions. Having more than one carboxylic acid species present in the mixture meaningfully changed the solid–liquid equilibrium versus temperature of the system. The carboxylic acids partitioned between the solid phase and the liquid phase and a practical design would require multiple duty-controlled solid–liquid equilibrium stages, with most of the separation taking place in the temperature range 0 to − 5 °C.

In this study, deep eutectic solvents (DESs) were prepared using choline chloride as hydrogen bond acceptor (HBA) and ethylene glycol (EG) or glycerol (GLY) or urea (U) as hydrogen bond donor (HBD) and were evaluated as solvents in the extraction of benzene from n-hexane. Six of such solvents were prepared using different molar ratios of HBA: HBD and code named DES1, DES2, DES3, DES4, DES5 and DES6. Liquid–liquid equilibria (LLE) data for the ternary systems of n-hexane-benzene-DESs were measured at 303 K and 101.3 kPa. Solubility data and mutual solubilities between n-hexane and DES were measured using the traditional cloud point method. The tie lines were obtained using titration and refractive index measurements on both phases (n-hexane phase and DES-phases). The ternary systems exhibit type-1 phase behavior. The Othmer-Tobias and Hands equations were applied to examine the reliability of the LLE data. The tie-line data were correlated using the nonrandom two-liquid (NRTL) and universal quasichemical (UNIQUAC) thermodynamic models, and their corresponding binary interaction parameters were determined. The results show that the maximum separation factors were 31.24, 462.00, 15.24, 37.83, 174.60 and 126.00 for DES1, DES2, DES3, DES4, DES5 and DES6, respectively. The glycerol based DES (DES2 and DES5) show the highest separation factors and thus considered the most suitable for separating benzene from hexane. The regression coefficient for both Othmer-Tobias and Hand equations are higher than 0.99 for all DESs, indicating the reliability and consistency of the data. Both NRTL and UNIQUAC models adequately capture the experimental data.

Light cycle oil (LCO) is an inexpensive feedstock for the production of high-added-commercial-value-mono-aromatic compounds such as benzene, toluene and xylenes (BTX). To extend the knowledge on the processing of LCO for BTX production, the hydrocracking reaction was studied using a commercial NiMo/Al2O3 catalyst, ZSM-5 zeolite and their mechanical mixtures (20/80, 30/70 and 50/50) for processing tetralin as model feedstock in a bench-scale-trickle-bed reactor at 450–500 °C, 3.9–5.9 MPa, 1.3 1/h and H2/feed volume ratio of 168–267 m3/m3. Accessible, well-dispersed and strong Brönsted acid sites eased the hydrocracking of tetralin to BTX and the metallic hydrogenation functions from nickel–molybdenum catalysts were also required to minimize deactivation. To achieve suitable tetralin conversions (86–95 wt%), high BTX selectivity in the liquid phase (44–70 wt%) and suitable catalytic activities for coke precursor hydrogenation (to reduce deactivation), NiMo/Al2O3//ZSM-5 mixtures (50–80 ZSM-5) were employed, which probed to be effective.

A Schiff base containing the 1,2,4-triazole moiety was synthesized and added to polystyrene at low concentration for a homogenous blend. The polystyrene film was irradiated with ultraviolet light and the surface morphology was analyzed. Micrographs of the polystyrene/Schiff base blend after irradiation indicated the fabrication of a terrestrial crack-like material. This was ascribed to the presence of the Schiff base, relatively long irradiation time, and photostability induced by the base. After irradiation, the blank polystyrene film formed a cotton-like fibrous material.

For the proper working of the internal combustion engine, engine oil plays a significant role. The performance of the engine is greatly affected by oil that has degenerated. In order to determine the optimal gap between oil changes, it is crucial to measure the deterioration in the engine oil. Multiple parameters like oxidation, nitration, viscosity and so on are brought into use. One of the methods used to quantify the deterioration in the engine oil is the Fourier Transform Infrared (FTIR) spectroscopy. The main parameters of the engine oil are distinguished by this method by utilizing Infrared (IR) absorption at different bandwidths. The two significant parameters in engine oil deterioration are oxidation and nitration. However, the limitation of the FTIR method is that it is more expensive and since it uses huge machinery, it requires a lot of area. Hence, the use of this method is not possible in the field area due to the need for space. It is this major limitation that is the motivation for proposing an inexpensive, yet handy system, using an IR sensor set up, in this paper. This system is used for measuring the transmittance of engine oil that has degenerated. For this paper, we collected random samples at various times from service stations that were specifically authorized. These samples were used in experiments based on the FTIR spectroscopy and UV spectrophotometer and the results were compared using the IR sensor setup. Investigation of the experimental results showed that monitoring oil transmittance using an IR sensor setup is possible, and a robust relationship between oxidation and nitration and the transmittance of the oil was observed. Moreover, a pattern of deterioration for a specific engine oil (SAE 5W30) which is utilized for passenger cars and light duty vehicles was also established.

AbstractToday, one of the challenging issues all over the world is the global warming which can be attributed to the emission of greenhouse gases into the environment as well as burning of gases in flare gas stream of industrial units. The latter can not only cause environmental problems but also is accompanied by wasting a great deal of energy. To deal with the aforementioned issue, the flare gas stream can be recycled after separating some species. In this investigation, the objective is to separate CO2 and H2 from the flare gas in addition to methanol production. In this regard, a separation with sorbent/solvent method is used which is divided into two stages: (1) H2 separation by sorbent, (2) CO2 separation by monoethanolamine solvent. From the obtained results in this study, in the first stage, H2 and CO2 can be purified up to 75% and 99.83%, respectively. Beside, methanol synthesis is compared in three different cases: (1) industrial unit, (2) CO2 is fed into the reactor instead of CO, and (3) CO2 and H2 are fed to the reactor with stoichiometric coefficients. The obtained methanol production of the case (1) is approximately close to that of the case (3) and it is reduced 4% in case (3).Graphic abstract

Converting plastic wastes into fuels through catalytic cracking is continuously gaining interest from researchers worldwide. In this study, the influence of iron on ZSM-5 (Fe-ZSM-5) catalyst on the reforming of the gaseous products of thermal decomposition of low-density polyethylene (LDPE) was investigated. The acidified ZSM-5 catalysts (0, 0.3, 0.6 and 1 wt% of Fe) were prepared and characterized by XRD, BET, FTIR and SEM techniques. In particular, the effects of temperature (400, 450 and 500 °C) and catalyst loading (0.5, 0.75, 1.0, 1.25 and 1.5 g) on a two-stage (pyrolyser and reformer) decomposition of the LDPE wastes into fuel were studied. The liquid fraction produced was characterized using FTIR and GC/MS techniques. The study showed that the increase in pyrolysis temperature (400–500 °C) increases the volume of non-condensable gas (31–58 wt%) and decreases the volume of the condensates (69–41 wt%) in both the thermal and catalytic pyrolyses. However, the trend was at higher level for the catalytic pyrolysis. The increase in temperature for the thermal pyrolysis had less significant effect on the aromatization content of the liquid condensate compared to the catalytic pyrolysis. The FTIR results show a significant increase in aromatic contents and decrease in the aliphatic of the liquid fraction for the catalytic pyrolysis reforming when compared with thermal pyrolysis. The GC/MS results confirmed the aromatic hydrocarbon compositions, predominantly p-xylene, increased relatively to about 70% in the liquid fraction for the best catalyst (1.25 g of catalyst and 1 wt% iron loading on ZSM-5 at 450 °C).

Deep eutectic solvents (DESs) have high viscosities, but known to be mitigated by addition of suitable co-solvent. The effect of such co-solvent on the extraction efficiency of the hybrid solvent is hardly known. This study examined the effect of ethanol on three choline chloride-based DESs (glyceline, reline, and ethaline) by mixing each in turn with ethanol in various volume proportions. The hybrid solvents were evaluated for the extraction of benzene from n-hexane. Pseudo-ternary liquid–liquid equilibrium data were obtained using the refractive index method at 303 K and 1 atm for the systems, n-hexane (1) + benzene (2) + hybrid solvent (glyceline/ethanol, ethaline/ethanol, reline/ethanol) (3), and used to evaluate distribution coefficient (D) and selectivity (S). Furthermore, the physicochemical properties of the hybrid solvents were also determined. The results indicate increase in selectivity with increasing ethanol addition up to 50% and decrease with further addition. All hybrid solvents with 50% ethanol outperform sulfolane and are suitable replacement for same as green and sustainable extractant for aromatics from aliphatics. The glyceline + 50% ethanol emerged the overall best with 49.73% elevation in selectivity and 41.15% reduction in viscosity relative to the neat glyceline. The finding of this study is expected to fillip the drive for paradigm shift in petrochemical industries.

The transhydrogenation of pentane (P) and 1-hexyne (1HY) was investigated over 4% CrOx/Al2O3 and potassium-doped 4% CrOx/Al2O3 catalysts over a range of temperatures (523–773 K) with a 5:1 P:1HY ratio. Over the CrOx/Al2O3 catalyst, transhydrogenation clearly occurred at temperatures below 625 K where the yield of alkenes was higher for the co-fed system than for a combination of the individual yields. Due to the acidic nature of the alumina, many of the products were alkylated olefins and alkylated hydrocarbons formed by coincident alkylation and isomerisation. When pentane was added to a feed containing 1-hexyne, the extent of carbon deposition was reduced. By comparing transhydrogenation to limited hydrogen 1-hexyne hydrogenation at 623 K, it was shown that the processes of hydrogenation and transhydrogenation were different, with hydrogenation favouring alkanes, while transhydrogenation favoured alkenes. This may be because pentane dehydrogenation only releases two hydrogen atoms, which only allows 1-hexyne to hydrogenate to 1-hexene. Therefore, if the rate of alkene isomerisation and desorption is faster than that of pentane dehydrogenation, only alkenes will be observed. The latter proposal would suggest that the dehydrogenation/hydrogenation process is closely coupled and would be consistent with pentane influencing 1-hexyne surface chemistry. The effect of the potassium doping was to increase the yield of alkenes. The reason for this may be related to changes in the nature of the surface chromia species. The potassium also neutralised the acid sites on the alumina, reducing the extent of alkylation and hydrogenolysis, which suppressed the formation of other alkynes in the product mix.

A heterogeneous spent soda effluent generated from Tunisian petroleum refineries has been filtrated and separated in four solid fractions with a particle diameter of 160 to 100, 100 to 40, 40 to 16 and 16 to 10 µm and the fifth one with diameters < 10 µm obtained after total evaporation of the remained filtrate. Spectroscopic characterizations of the condensed phases by means of X-ray induced photoelectron and IR absorption, as well as pH-metry, potentiometry and stationary voltammetry at Ag2S/Ag electrode studies of the filtrate, show that the whole of the separated fractions contain Na2S, NaHS, C2H5SNa, Na2S2O3, Na2SO3 and methyl, ethyl and propyl mercaptans.

The study of a light cycle oil (LCO) upgrading alternative involving hydrotreating and hydrocracking/transalkylation procedures for obtaining a benzene, toluene and xylene (BTX) enriched fraction is presented. The research work was focused on the effect of the experimental conditions on the hydrocracking of an hydrotreated light cycle oil (HDT LCO) in order to produce the highest amounts of BTX, when the catalysts consisted of a mixture (50/50 in weight) of nickel–molybdenum on alumina (NiMo/Al2O3) and ZSM-5 materials (NiMo/ZSM-5 (50)). It was found that 7.4 MPa, up to 375 °C, LHSV of 1.2 h−1 and a H2/Oil value of 442 m3/m3 were the optimal experimental conditions for producing an enriched BTX fraction (31%). In order to facilitate the analysis, the study was carried out considering four types of hydrocarbons as lumps for the feed and HCK products: light hydrocarbons (LHC) composed by C4–C7 non-aromatic compounds, BTX, middle hydrocarbons (MHC) consisting of C7–C10 paraffins and isoparaffins, alkylbenzenes, tetralin and naphthalene derivatives and a small amount of high molecular weight hydrocarbons (HHC). Based on this description, HDT LCO used as feedstock for the hydrocracking (HCK) procedure, presents a 99% of a MHC fraction. The HCK conversion, BTX selectivity and yields were obtained from the chromatographic analysis of the products. A simple kinetic model considering only the MHC conversion was carried out. The obtained activation energy confirmed the endothermic nature of the HCK process. The activity decay of the catalytic mixture was also studied by varying the time on stream.

The adipic acid (AA) production was carried out in two stages: oxidation of cyclohexanone (-one) by Keggin-type polyoxometalate (POM), followed by oxidation of this latter by hydrogen peroxide. The process lasts 20 h and the temperature is maintained at 90 °C. AA is then recovered by cold crystallization (4 °C). The POMs have as formula HMPMo12O40 (M:Co, Ni, Mn, Cu or Zn). The materials were characterized by FT-IR and UV–Vis spectroscopies and by thermogravimetric analysis. The purity of adipic acid was confirmed by FT-IR and 13C and 1H NMR analysis. The effects of POM composition, catalyst/-one molar ratio and the cyclohexanol addition to -one on adipic acid yield were examined. The whole catalysts were found to be effective toward cyclohexanone oxidation and the highest yield (53%) was obtained with HZnPMo12O40 system for a catalyst/-one molar ratio of 1.89 × 10−3. The alcohol addition to -one has a negative effect on adipic acid formation.

Three bio-based crude oil emulsion breakers have been prepared from agricultural waste by chemical treatment of cashew nutshell liquid (CNSL) extract with triethanolamine via a one-pot reaction at 120 ℃. The triethanolamine-ester derivatives were characterized by Fourier Transform–InfraRed spectroscopy. Their effectiveness as crude oil emulsion breakers were investigated experimentally using the bottle test method. The effect of solvent type, water content, and concentration of the emulsion breaker, was used to study the demulsification process and determine their demulsification efficiency at a temperature of 60 ℃ for a contact time of 180 min. A commercial demulsifier, PhaseTreat 4633 (PT-4633) was used as a benchmark. Performance evaluation of the prepared emulsion breakers revealed their effectiveness in descending order as: triethanolamine dianacardate (TED) > triethanolamine trianacardate (TET) > triethanolamine anacardate (TEA). The data reveals that their emulsion breaking efficiency increases with increasing emulsion water content, and concentration. PT-4633 exhibited better demulsification efficiency than the triethanolamine-esters in xylene across the concentration and water content studied. Improved water separation was however observed for the triethanolamine-esters in butanol, as triethanolamine trianacardate (TET) performed better than PT-4633 at 10 ppm to 20 ppm at 30% water content with a water separation of 83.33% and 80% respectively. The evaluated triethanolamine ester derivatives exhibited better emulsion breaking potentials in butanol than xylene at shorter times, which may be due to the synergistic effect of butanol. Therefore, butanol could be used as a sustainable solvent substitute for xylene in demulsifier formulations.

AbstractThe consequences of increased fossil fuel consumption on the environment presents a challenge. Carbon dioxide capture is a useful technique to reduce global warming. Therefore, three carvedilol metal (nickel, cobalt, and copper) complexes were synthesized as potential carbon dioxide storage media. The structural and textural properties of metal carvedilol complexes have been established using various techniques. The metal complexes have mesoporous structures in which pore size was approximately 3 nm. Particle size ranged from 51.0 to 393.9 nm with a relatively small surface area (6.126–9.073 m2/g). The carvedilol metal complexes have either type-III or IV nitrogen adsorption–desorption isotherm. The complexes showed reasonable capacity towards carbon dioxide uptake (up to 18.21 cm3/g) under the optimized condition (40 bar and 323 K).Graphical Abstract